Many activities associated with oil and gas operations contaminate the surface of nearby soil with water-soluble contaminates such as salts, acids, bases, metals, and the like. Such activities include produced water spills, SO.sub.2 scrubber emissions associated with steam generation, and the like. Salt contamination, particularly within the top sixteen inches of the soil, ie., shallow salt contamination, is detrimental to soil for a number of different reasons. For example, shallow salt contamination inhibits the growth of vegetation in the soil, and accelerates erosion of the soil. The detrimental effects of salt are accentuated in regions where evaporation exceeds precipitation, i.e., in arid regions, because evaporation wicks salt to the surface of the soil, and the salt is not flushed away through precipitation, such as rainfall, as it is in less arid regions.
There are a number of conventional techniques that may be employed to mitigate the foregoing contamination of soil. For example, as a preventative measure when a produced water spill occurs, vacuum trucks may be utilized to remove contaminated water from the soil before the water enters the soil. While such use of vacuum trucks is somewhat effective as a preventative measure, some contaminated water will inevitably still enter and contaminate the soil.
Once contaminants have entered the soil, the contaminants may be removed by excavating the soil, washing and flushing the soil, and restoring the soil to the ground. Such a process, however, is very expensive and, for most applications, is cost prohibitive. Alternatively, amendments such as gypsum may be mixed into the soil to convert contaminants, such as sodium chloride salt (NaCl), into less detrimental substances. The converted contaminants, however, may still be detrimental, albeit less detrimental, to the soil. Furthermore, because amendments do not rid the soil of the elements of the contaminants, it is possible that at some point in time the elements could be converted back into the original contaminants.
Therefore, what is needed is a process to economically decontaminate soil, particularly in arid regions, by removing contaminants from the soil.